1. Technical Field
The present invention relates to vehicle brake pressure controllers that previously sense brake timing with which a driver pressed a brake to brake wheels and supplies a brake pre-pressure that brings a friction member of a brake into slight contact or close to a rotating member.
2. Related Art
Conventional vehicle disc brakes generate what is called a drag when a brake pad remains in contact with a disc rotor under non-braking conditions. The drag not only serves as a resistance to degrade power performance but also contributes toward abrasion of the brake pad.
Therefore, under the non-braking conditions, a return spring separates the brake pad from the disc rotor with a predetermined gap. However, when the driver steps a brake pedal, the brake clearance between the brake pad and the disc rotor becomes an invalid stroke to generate a braking delay. Therefore, the brake clearance is preferably narrowed to a minimum.
For example, Japanese Unexamined Patent Publication (JP-A) No. 2002-321609 discloses a technique for performing what is called a first fill operation. Specifically, at an early stage when the driver presses the brake pedal, brake fluid is rapidly supplied to the brake from a master cylinder to immediately cover the invalid stroke of the brake pedal.
For another example, JP-A No. 2001-239929 discloses motor-driven brake control. Specifically, when the driver presses the brake pedal, firstly position control performed to bring the brake pad close to the disc rotor and then power control is performed to press the brake pad against the disc rotor.
However, the technique disclosed in JP-A No. 2002-321609 requires a brake fluid pressure chamber in the master cylinder in order to perform the first fill operation, which complicates the structure, increases in size the master cylinder, and increases product cost.
The technique disclosed in JP-A No. 2001-239929 requires an electric motor, which increases the number of components and the weight, and the installation of the electric motor constrains the layout of components.